It's a type of social influence where individuals or an individual can yield to group pressure which can either be real or imagined.
It can result in a change in a persons behaviour, beliefs or both.
They're informal rules that people and groups adopt to regulate other people or group members behaviours. Sanctions are things to punish those who do not comply with these norms.
It can vary from - Waiting for your turn, Remaining quite when needed, aka at a funeral or on a bus, and Maintaining interpersonal distance.
Internalisation, Identification and Compliance.
The process of making a beliefs or attitudes a part of someones nature, whether they believed different before or not, by learning or by unconscious assimulation.
Where one changes their public behaviour and private behaviour, due to them valuing the membership they have within a group. This may change if the person leaves that group of setting.
An individual may agree publically with a group however may privately diagree.